Centrifugal separator



Jan. 17, 1939. 1- G; w. RUDA 2,144,229

CENTRIFUGAL SEPARA'IOR Filed Jan. 9, 1935 2 Sheets-Sheet l @anla/JMJan.17,1939. GLWRUDA 1 d 2,144,229

' i GENTRIFUGAL'SEPARATOR Filed Jan. 9, 1955l 2 sheets-sheet 2 mien@ LMPatented Jan. 17, I1939 UNITED STATES 2,144,229 cem-nirvana sErAnA'ronGustafwnheimnuas, stockholm, sweden, ag-

v signor to The De Laval Separator' Gompany, New York, N. Y., acorporation of New Hersey Application January 9, 1935, Serial No. 95d InSweden June 16, 1,934A

'1 claims. (o1. 23a-4s In separators of the type in which the separatedliquids are thrown out from the separator bowl and collected incollecting vessels, air is admixed with the discharging liquid, andcauses a con siderable froth, so that the separated liquid becomes lesssuitable for subsequent treatment. This condition is particularlycharacteristic of the centrifugal separation of milk.

In so-called closed separators, .the separated liquids are dischargedfrom the bowl without passing through any air layer. Liquids separatedin this way are practically free from froth, whereas after separationin. separators provided with free outlets 40 to 50% of froth is notunusual.

In the separation of milk 'it is especially the skim milk that has atendency for formation of froth. The tendency of the cream to form frothis not so pronounced, and in' many cases the cream discharged from'bowls provided with open outlets is in satisfactory condition. Moreover,a substantial aeration of the cream may be useful and desirable and thisaeration occurs when the cream discharges freely.

The present invention is one adapted to prevent froth formation in theskim milk without avoiding such limited froth formation in the cream asis consistent with a desirable degree of aeration.

Ihe invention also has for its object the provision of controllablemeans to allow recirculation of skim milk through the separator.

The invention also has for its object to provide such construction andarrangement of the parts of a centrifugal machine as will cause therevolving separator bowl to act as a suction pump for the liquid to beseparated. l

The invention also comprises certain novel structural features wherebythe above objects 0 are most eiliciently attained.

In the drawings:

Fig. 1 is a longitudinal sectional, view of a centrifugal separatingmachine embodying my invention. y y

Fig. 2 1s a. longitudinal sectional view or the upper part ofamodification of Fig. l.

Fig. 3 is a cross-section on the line l3--3 of Fig. 1.

Fig. 4 is a cross-sectional view of a modification of the elements shownin Fig. 3.

Fig.' 5 is a longitudinal sectional view of a part of a separatorcomprising a modified construction for sealing the bowl against ingressof air.

Referring to Fig.'1: the main frame body I is provided with a cover 2which may be hinged 1 for the skim milk. Vessel 1 is covered by a lid 108 held in place by the lock ring 9. The skimmer device I0, which isfixedto the top cover 4, projects into the chamber 1 and is maintainedin position by the tension of the central milk inlet tube I I, intowhich the nozzle I2 of the regulating l5 vessel 5 is threaded. If theWhole milk fed in through the feed tube II passes through an airlayer inthe distributor I3 of the bowl 6, and if ythe distributor communicateswith the outer atmosphere, air is sucked in and causes a formao tion` offroth in the cream and the skim milk. To prevent this source of frothformation, the lower part of the milk feed tube II is provided with aflange I4 having so large a. diameter that, during separation, itprojects into the body of 25 milk contained in the bowl or in theenlarged lower part of the distributor from which the bowl is directlyfed. In this way a liquid sealed passage is formed between the feed tubeII and the Y separator bowl 6. .30

The cream separated out in the bowl is conducted into the neck of thetop disc I5 to outlets I6 therein located below the collecting chamber 1for the skim milk. To obtain a free passage for the cream to thecollecting vessel 3, the bowl neck 35 is milled through immediately infront of outlets I6. See Fig. 3. In this figure the channels 2B forconducting the skim milk to the vessel l are formed entirely within thebowl neck 32. In Fig. 4 similar channels 33 are formed by grooves'in 40the inner wall of the bowll neck 32, which are closed by the neck of thetop disc i5.

For regulating the percentage of cream the skim milk outlet is providedwith a regulating valve I1, which is preferably of such construction 45that it can also be .used as a reversing valve,

which is necessary for generating a circulation of liquid through thebowl. In. Fig. 1 this valve is shown as a three-way valve located at-thejunction of channel 34 communicating with the skim- 50 mer I0, a skimmilk -discharge pipe 35, and a skim milk return pipe 36 communicatingwith the whole milk supply vessel 5. This combined regulating andreversing valve is provided with three-way openings of such areasrelative to the i diameter of the valve casing and the areas of thethree openings therein that it is possible to so position the valve asto maintain a predetermined counter-pressure in the skim milk channel 34and skimmer III while at the same time it cannot be turned into suchposition as to shut olf outflow of skim milk or so as to so greatlythrottle the flow asto cause the skim milk to overflow the inner edge ofthe collecting vessel 1.

The whole milk is fed into the regulating vessel 5 through the supplytube 31. The float I 9 maintains a fixed level in the regulating vesselso that the supply of liquid into the bowl is constant. The milk flowsfrom the regulating vessel 5 through the feed tube II down into theseparator bowl 6. The skim milk is conducted between the top disc I5 andthe bowl hood 3| up to the channels 20, which open into the collectingchamber 1. The skim milk is discharged from the collecting chamber 'I bythe skimmer device Il. The counter-pressure in the discharge pipe, andthus the cream percentage, are regulated by the valve I1.

The cream discharges through the outlets I6 in the top disc and iscollected in the collecting vessel 3, whence it flows out through thespout 2 I.

In another embodiment of the invention shown in Fig. 2, feed tube II,-oran extension I8 thereof, is connected airtightly with a pipe line 22rimning to the milk container (not shown). If, in this embodiment, aflange I4 is provided on the lower end of the supply tube II, or if aclosed communication between the separator bowl I and the feed tube IIis established by means of a liquid seal or tightening arranged in anyother way. a self-sucking separator bowl is obtained, and a whole-milkpump need not be used. In order to obtain the vacuum in the supply tubewhich is necessary for the suction, the valve I1 should be adjusted toconnect the skim milk-outlet with a return tube, or circulation tube,23, which is tightly connected with a vessel 24 having a funnelcommunicating with extension I8 of feed tube I I. When the separation isstarted so much liquid is filled into the bowl through the funnel 24that the circulation commences. When the circulation has continued forsuch time that the liquid flowing through the bowl has brought away somuch air that the vacuum in the pipe line 22 has become sufficientlygreat to suck liquid from the container, the valve I'I is reversed andthe funnel 24 is shut off from pipe I 8 by a Valve 2l. In order that thethroughput shall be constant a constant vacuum must be maintained in thesuction pipe. This is obtained by providing the suction p ipe 22 with anair valve 26, which is adjusted for a given vacuum.

In Fig. 5 is shown an alternative construction for providing a liquidseal between the feed pipe and the separator bowl. 40 is the expandedlower end of the distributor 42', which is provided with inwardlyprojecting lateral flanges 43 alternating with outwardly projectinglateral flanges 44 on the feed tube 4I; these flanges extending into achamber 46 integral with or secured to the distributor 42. This chambercommunicates at its lower end with the feed tube 4I and with theexpanded lower end of the distributor, from which the bowl (not shown)is fed. Skim milk from the feed tube fills this chamber to the extentrequired to cover the overlapping ends of the flanges. The chamber 46which is spaced, throughout part of its circumference, from the innerwall of the distributor 42, is provided with a skirt 4l extendingoutward beyond the normal level of the liquid in the expanded lower endof the distributor. By means of this construction, liquid seals areprovided, effective to exclude admission of air into the separator bowl.

While, in describing the invention, I have assumed the separation ofwhole milk into cream and skim milk, it will be understood that theinvention is not limited to such separation, as it may be utilized toequal advantage in the separation of the constituents of other mixtures.The details of construction described may also be varied, within thescope of the appended claims, without departing from my invention.

What I claim and desire to protect by Letters Patent is:

1. A centrifugal separator comprising a rotatable bowl, a bowl feedhaving a portion adapted to be surrounded by liquid in the bowl andthereby cut off from communication with the atmosphere, a skimmer bymeans of which one ofthe separated liquids is removable from the bowl, adischarge channel communicating with said skimmer, a discharge pipe anda retuni pipe, the latter communicating with said bowl feed, and athree-way valve positioned at the junction of said channel and saidpipes by means of which the liquid outflowing through said channel maybe diverted from the discharge pipe to said bowl feed, the areas of thevalve openings and the diameter of the valve casing being soproportioned as to enable the valve to be positioned to maintain apredetermined counter-pressure in said channel.

2. A centrifugal separator comprising a rotatable bowl, a bowl feed, askimmer by means of which one of the separated liquids is removable fromthe bowl, a discharge channel communicating with said skimmer, adischarge pipe and a return pipe, the latter communicating with saidbowl feed, and a three-way valve positioned at the junction of saidchannel and said pipes by means of which the liquid outflowing throughsaid channel may be diverted from the discharge pipe to said bowl feed,said valve and the openings controlled thereby being so proportioned asto prevent such substantial closure of the valve as would create acounter-pressure in the channel and skimmer -exceeding a predeterminedmaximum.

3. A centrifugal separator comprising a rotatable bowl, a bowl feed,means to maintain a liquid seal preventing communication between theliquid conveyed by the bowl feedvand the atmosphere, a skimmer by meansof which one of the separated liquids isremovable from the bowl, a 5

connection between the skimmer and the bowl feed adapted to be closed,and a suction pipe communicating with the bowl feed and adapted toconvey thereto liquid mixtures to be separated, whereby the rotatingbowl is adapted to act as a suction pump for the liquid to be separated.

4. A centrifugal separator in accordance with claim 3 wherein saidclosed connection comprises a pipe, a receiver provided with a funneland a valve adapted to close communication between the funnel and thebowl feed.

5. A centrifugal separator in accordance with claim 3 including also aregulating valve for maintaining a constant pressure in the suctionpipe.

6. A centrifugal separator in accordance with claim 3 including also anoutlet pipe for said separated liquid and a valve by means of which saidseparated liquid may be diverted through said connection.

7. A centrifugal separator comprises a rotatable 75.

bowl, a. bowl feed for liquid mixtures to be separated, means tomaintain `a liquid seal connecting the liquid conveyed by the bowl feedand the liquid in the bowl and preventing the entrance of gases, askimmer by means of which one of the separated liquids is removable fromthe bowl,

a discharge channel communicating with said skimmer, a. discharge pipeand a return pipe, the latter communicating with said bowl feed, andmeans to convey to 'either pipe the separated liquid conveyed by theskimmer to said channel. 5

GUSTAF WILHELM RUDA.

